Figuring plow size for a 4320 CUT JD

I'm looking at buying a breaking (or turning as some may call it) plow for my 4320. What I'm wondering is the size to buy.

I've read to allow 1" of pan per PTO horsepower. In my case, figuring the 4320 = approximately 48 hp, the 4320 should pull a plow with 3 - 16" pans or the equivalent.

Of course, YMMV, depending on soil type, condition, weight of tractor, fluid in wheels etc. Dad thinks my tractor will pull it all right if it has enough weight to provide the traction needed.

Anyone with any experience or other thoughts?

Re: Figuring plow size for a 4320 CUT JD

Tue Aug 02, 2011 7:37 am

Wayne, I do not have the figures for figuring that, but do have some practical experience on the old tractors in soils such as we have in M. with the rock and red clay in them. A Farmall H (25 hp) would pull 2 14 inch bottoms, or if it had the high compression kit could pull 2 16 inch bottoms, or a little bigger in river bottom ground. Farmall M (35 drawbar hp) would handle 3 14 inch bottoms. Don't forget about weights, most modern tractors have quite a bit of HP for running ptos. etc. but are not real heavy on the rear wheels which you will need for traction.

Re: Figuring plow size for a 4320 CUT JD

Tue Aug 02, 2011 7:52 am

bamabww wrote:I'm looking at buying a breaking (or turning as some may call it) plow for my 4320. What I'm wondering is the size to buy.

I've read to allow 1" of pan per PTO horsepower. In my case, figuring the 4320 = approximately 48 hp, the 4320 should pull a plow with 3 - 16" pans or the equivalent.

Of course, YMMV, depending on soil type, condition, weight of tractor, fluid in wheels etc. Dad thinks my tractor will pull it all right if it has enough weight to provide the traction needed.

Anyone with any experience or other thoughts?

Are you sure your numbers are right? A 4320 has 100 HP on the drawbar, and will pull a 10 shank chisel plow.

Re: Figuring plow size for a 4320 CUT JD

Tue Aug 02, 2011 8:22 am

Mike, that was my thinking too, but I thought that maybe John Deere has assigned that model # to a newer & smaller tractor. They've had so many different model numbers in recent years that I lost track a long time ago. At any rate, the calculation seems reasonable, depending on soil type and other variables.

Re: Figuring plow size for a 4320 CUT JD

Tue Aug 02, 2011 8:23 am

I would talk to a couple of adjacent old farmers. They will know about area soil types and if the ground has been previously worked - they will be able to tell you about the tractor and plow used.

Re: Figuring plow size for a 4320 CUT JD

Tue Aug 02, 2011 8:58 am

Gary Dotson wrote:Mike, that was my thinking too, but I thought that maybe John Deere has assigned that model # to a newer & smaller tractor.

Yeah, the CUT = Compact Utility Tractor not the full blown 4320 you were thinking of Mike. My 4320 is a good bit smaller than the original 4320.

Re: Figuring plow size for a 4320 CUT JD

Tue Aug 02, 2011 10:56 am

I see, I overlooked the "CUT". Deere has a bad habit of re-using numbers.

If it is all wheel drive it will pull more bottoms than the HP suggests.

Re: Figuring plow size for a 4320 CUT JD

Tue Aug 02, 2011 11:36 am

not being familiar with the newer JD, I assumed the CUT was referring to plow cut. OOPS

Re: Figuring plow size for a 4320 CUT JD

Tue Aug 02, 2011 12:54 pm

Virginia Mike wrote:If it is all wheel drive it will pull more bottoms than the HP suggests.

Good point. It is a 4WD. I have found the plow pictured in the original post for $275 and it is solid as a rock. I'm going to ask the guy if I can "try before I buy" and see just how the tractor pulls the plow in my red clay.

Re: Figuring plow size for a 4320 CUT JD

Re: Figuring plow size for a 4320 CUT JD

Tue Aug 02, 2011 5:38 pm

Well, if you crack open Deere's implement brochure to go with that tractor, you find a 2 bottom plow listed. Keep in mind that horsepower is needed for speed and most modern plows are designed for higher speed than the older ones.